import numpy as np
from numpy.lib import stride_tricks
from matplotlib import pyplot as plt
import scipy.io.wavfile as wav


"""
This script creates spectrogram matrices from wav files that can be passed
to the CNN. This was originally created  by Frank Zalkow and revised by JINJing
"""


def stft(sig, frameSize, overlapFac=0.5, window=np.hanning):
    """
    Short-time Fourier transform of audio signal.
    """
    win = window(frameSize)
    hopSize = int(frameSize - np.floor(overlapFac * frameSize))
    # zeros at beginning (thus center of 1st window should be for sample nr. 0)
    samples = np.append(np.zeros(np.floor(frameSize/2.0)), sig)
    # cols for windowing
    cols = np.ceil((len(samples) - frameSize) / float(hopSize)) + 1
    # zeros at end (thus samples can be fully covered by frames)
    samples = np.append(samples, np.zeros(frameSize))

    frames = stride_tricks.as_strided(samples, shape=(cols, frameSize),
                                      strides=(samples.strides[0]*hopSize,
                                      samples.strides[0])).copy()
    frames *= win

    return np.fft.rfft(frames)


def logscale_spec(spec, sr=22050, factor=20.):
    """
    Scale frequency axis logarithmically.
    """
    timebins, freqbins = np.shape(spec)

    scale = np.linspace(0, 1, freqbins) ** factor
    scale *= (freqbins-1)/max(scale)
    scale = np.unique(np.round(scale))

    # create spectrogram with new freq bins
    newspec = np.complex128(np.zeros([timebins, len(scale)]))
    for i in range(0, len(scale)):
        if i == len(scale)-1:
            newspec[:, i] = np.sum(spec[:, scale[i]:], axis=1)
        else:
            newspec[:, i] = np.sum(spec[:, scale[i]:scale[i+1]], axis=1)

    # list center freq of bins
    allfreqs = np.abs(np.fft.fftfreq(freqbins*2, 1./sr)[:freqbins+1])
    freqs = []
    for i in range(0, len(scale)):
        if i == len(scale)-1:
            freqs += [np.mean(allfreqs[scale[i]:])]
        else:
            freqs += [np.mean(allfreqs[scale[i]:scale[i+1]])]

    return newspec, freqs


""" plot spectrogram"""
def plotstft(audiopath, binsize=2**10, plotpath=None, colormap="jet"):
    samplerate, samples = wav.read(audiopath)
    print(samplerate)
    s = stft(samples, binsize)

    sshow, freq = logscale_spec(s, factor=1.0, sr=samplerate)
    ims = 20.*np.log10(np.abs(sshow)/10e-6)  # amplitude to decibel
    timebins, freqbins = np.shape(ims)

    plt.figure(figsize=(15, 7.5))
    plt.imshow(np.transpose(ims), origin="lower", aspect="auto", cmap=colormap, interpolation="none")
    plt.colorbar()

    plt.xlabel("time (s)")
    plt.ylabel("frequency (hz)")
    plt.xlim([0, timebins-1])
    plt.ylim([0, freqbins])

    xlocs = np.float32(np.linspace(0, timebins-1, 5))
    plt.xticks(xlocs, ["%.02f" % l for l in ((xlocs*len(samples)/timebins)+(0.5*binsize))/samplerate])
    ylocs = np.int16(np.round(np.linspace(0, freqbins-1, 10)))
    plt.yticks(ylocs, ["%.02f" % freq[i] for i in ylocs])

    if plotpath:
        plt.savefig(plotpath, bbox_inches="tight")

    plt.clf()

    ims = np.transpose(ims)
    ims = np.flipud(ims)  # weird - not sure why it gets flipped
    return ims


if __name__ == '__main__':
    wav_file = 'static/audio_uploads/Vocaroo_s0er01Jq27Z2.wav'

    plotstft(wav_file, plotpath='static/img/so_cool.png')